Insulinoma in chronic renal failure: a case report.

The diagnosis of insulinoma depends on the fulfillment of well-established criteria during the 72-h fast. However, these criteria rely on normal renal function. Spontaneous hypoglycemia that is not attributable to insulinoma may occur in persons with renal failure. We describe herein a patient with renal impairment who had undergone renal transplant and had a 20-yr history of hypoglycemic symptoms and successful resection of insulinoma. Although the results of a 72-h fast were consistent with endogenous hyperinsulinemia, their interpretation was complicated in the presence of renal impairment. Fortunately, the identification of the tumor, by endoscopic ultrasonograph, led to a correct diagnosis. This case seems to be the second report of a patient with insulinoma with concomitant renal failure.